Process of preparing negatives for sand-blast engraving.



UNITED STATES PATENT OFFICE. iomnn'nnmmcn FREY Ann ERNST rannor scnarrnAusnn, swrr znamnn. raocnsa or 'rnnraamo mtearrvns'roa snNn-nms'r nueaavme.

- i p ecificationioi ltetteri l'atent.

PatentedN-ov. 10, 1908.

amt-ma sacmamas, rm. Serial No. 394,544.

I Teellwiiom r Be it known thatwfe, Johann Hammer: Fan and Enns'r Fnnr,1citizens of the Confederation-i Switzerland, residingin'Schafis hausen, Switzerland, have invented I certain new and Improvements N tive e jar Susanna-Enew w s 1 invention relates-to an improved by means of which drawings and prmtemay betransferred to a surface to be engraved by the sand-blast process. The surface to be engraved is covered with a thin of glatin sensitive to light, andthe ob ect of t e mvention' is to provide 'a process y rneans of which drawings and rints are prepared for being heliographica ly trans- -erredtothisfilm.;'

It has been found that none of the inks hitherto used for printing or drawing, even the best black ink, is suihcientl opa ue for this transferring. process. on a such mks produced by known means are used and exposed to electric light the violet and ultravioletrays penetrate the ink and a sharply defined latin relief is not obtainable.

Accor ing to the present invention, for

the characters or the drawings, so called 1i lit-filter inks are emplo ed, 1'. e., inks w ich, when ap lied in a t ick layer, have the property 0 absorbing. all chemically active ra s. These inks are preferably com- 0 two parts of glycerin and three parts of gum arabic, completely saturated with an alcoholic solution of a suitable anilin color, such as aurantia or spirituous orange-red, but cannot, however, be used with ordinary transparent tracin papers, as these latter will not absorb the According to the resent invention, this difl'iculty is overcome y. using tissue-pa r which will absorb the ink to a great epth, without spreading, and which hasfurther properties rendering it suitable for use with the process.

produced, and vice versa, so that such prints can be employed instead of the originals. This is effected by the present invention as follows: The drawing or impression is gone over with alight blue gum-printing ink, dusted over with dextrin and dried. After being dried the paper is stretched in a frame. By means of a spraying device an alcoholic solution of shellac, saturated with an anilin color, such as aurantia or spirituous red,is then uniformly applied, this taking butlittle time, aboutone-half aminute forlOOO sq. cm. .After a lapseof a quarter of an hour the tracing can be developed in ordinary water. As soon as the water has penetrated from the back to the gum and dextrin these "suhs tances swelLand burst the shellac layer and float ofi together with the superposed lager of color. At those portions not covered y the shellac adheres well and even enters into the tracing paper on Venetian turpentine being added, so that such tracings likewise form light filters. All good trans arent commercial tracing papers can be use for making these tracings.

For greater security or strength the tissuepaper impressions and likewise the shellacprints can be treated with bronze While still damp. V a

The further operation by means of the sand-blast, on the' plates, provided with the gelatin relief, is effected in the usual manner, and can be continued soas to efl'ect the engraving to the desired depth.

The resulting engravings are sharper and clearer than those of plates the designs of which have, as hitherto, been transferred mechanically.

Pictures can be transferred by the present process with a. great economy of time and labor as compared with previous processes.

Having thus described our invention, we claim as new and desire to secure by Letters Patent:

1. The process of preparing heliographic negatives for sand-blast engraving, which consists in producing a design on transparent 'aper in anilin ink containing a binding me ium.

2. The process of preparing heliographic negatives for sand-blast engraving, which consists in producing an ink design on tissue-paper, andthen rendering the tissuepaper transparent.

consists in producing an ink design on tissue-paper, rendering such tissue-paper transparent b a solution of grape-sugar, and

then rolling the paper while in a moist state onto the surface to be engraved.

4. The'process of preparing heliographic negatives for sand-blast engraving, which consists in producing a design on tissuepaper in anilin ink containing a binding medium, rendering such tissue-paper transparent by means of a solution of grapesugar, and then applying the pa 'er while moist to the surface to be engrave ,5. The process of producing heliographic negatives from positives, and vice versa, conscopes sisting in tracing over the design with gumprintmg ink, in covering the sheet provided with the design with a water-resisting resinous solution containing opaque anilin coloring-matter, and in immersing the sheet in water, whereupon the resinous filn is ruptured along the lines corresponding to the contour of the design. I

In witness whereof we have hereunto signed our names this 5th day of September, 19( in the presence of two subscribing witnesses. v JOHANN HEINRICH FREY. ERNST FREY.

Witnesses:

WILHELM Scnmn, A. LIEBERKNECHT. 

